In Hydrodynamic Response in irregular wave, the motion RAOs are calculated from the lower frequency to the upper frequency of the wave spectrum. Outside this frequency range, the RAOs are set to be zero, as it is assumed that there is no the first order wave exciting force at the wave frequency outside this frequency range of the wave spectrum. The lower and upper wave frequencies are listed in (your HR in irregular wave project)\FREQUENCY.LIS, in the format of
Please check in Hydrodynamic Response in irregular wave if there is any nonlinear drag being defined, which will be included in Hydrodynamic Response analysis if the linearized damping option is switched on.Â
In Hydrodynamic Response in irregular wave, it is automatically set 0.5% of critical damping if the total damping is less than it, which may also make slight difference of the peak of curve near the resonant frequency.
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